parking brake TOYOTA SIENNA HYBRID 2021 (in English) Service Manual

3254-5. Using the driving support systems
4
Driving
WARNING
●Do not replace a sensor with a
part other than a genuine part.
●Do not subject a sensor or its
surrounding area to a strong
impact.
●Do not damage the sensors,
and always keep them clean.
●If the area around a radar sen-
sor is subjected to an impact,
the system may not operate
properly due to a sensor mal-
function. Have the vehicle
inspected by your Toyota
dealer.
■Handling the suspension
Do not modify the suspension, as
changes to the height or inclina-
tion of the vehicle may prevent
the sensors from detecting
objects correctly or cause the sys-
tem to not operate or operate
unnecessarily.
■If the Parking Support Brake
function (static objects) oper-
ates unnecessarily, such as
at a railroad crossing
In the event that the Parking Sup-
port Brake function (static objects)
operates unnecessarily, such as
at a railroad cross ing, brake con-
trol will be cancele d after approxi-
mately 2 seconds, allowing you to
proceed forward and leave the
area, brake control can also be
canceled by depressing the brake
pedal. Depressing the accelera-
tor pedal after brake control is
canceled will allow you to proceed
forward and leave the area.
■Notes when washing the vehi-
cle
Do not apply intensive bursts of
water or steam to the sensor
area.
Doing so may result in the sensor
malfunctioning.
●When using a high pressure
washer to wash the vehicle, do
not spray the sensors directly,
as doing so may cause a sensor
to malfunction.
●When using steam to clean the
vehicle, do not direct steam too
close to the sensors as doing so
may cause a sensor to malfunc-
tion.
■When to disable the Parking
Support Brake
In the following situations, disable
the Parking Suppor t Brake as the
system may opera te even though
there is no possibility of a colli-
sion.
●When inspecting the vehicle
using a chassis roller, chassis
dynamo or free roller
●When loading the vehicle onto a
boat, truck or other transport
vessel
●If the suspension has been
modified or tires of a size other
than specified are installed
●If the front of the vehicle is
raised or lowered due to the
carried load
●When equipment that may
obstruct a sensor is installed,
such as a bumper protector (an
additional trim strip, etc.), hitch-
mounted bicycle carrier, or
snow plow
●When using an automatic car
wash

3264-5. Using the driving support systems
■The Parking Support Brake
function (static object) will
operate when
The function will op erate when the
PKSB OFF indicato r is not illumi-
nated ( P.93, 95) and all of the fol-
lowing conditions are met:
●Hybrid system output restriction
control
• The Parking Support Brake is enabled.
• The vehicle speed is approxi-
mately 9 mph (15 km/h) or less.
• There is a static object in the trav- eling direction o f the vehicle and
approximately 6 to 13 ft. (2 to 4 m)
away.
• The Parking Support Brake deter-
mines that a stronger-than-nor-
mal brake operation is necessary
to avoid a collision.
●Brake control
• Hybrid system output restriction
control is operating
• The Parking Support Brake deter- mines that an immediate brake
operation is necessary to avoid a
collision.
■The Parking Support Brake
function (static objects) will
stop operating when
The function will st op operating if
any of the following conditions are
met:
●Hybrid system output restriction
control
• The Parking Support Brake is dis- abled.
• The system determines that the collision has beco me avoidable
with normal brake operation.
• The static object is no longer approximately 6 to 13 ft. (2 to 4 m)
away from the vehicle or in the
traveling directi on of the vehicle.
●Brake control
• The Parking Support Brake is dis- abled.
• Approximately 2 seconds have
elapsed since the vehicle was stopped by brake control.
• The brake pedal is depressed after the vehicle is stopped by
brake control.
• The static object is no longer approximately 6 to 13 ft. (2 to 4 m)
away from the vehicle or in the
traveling direction of the vehicle.
■Re-enabling the Parking Sup-
port Brake function (static
objects)
 P.322
■Detection range of the Parking
Support Brake function (static
objects)
The detection range of the Parking
Support Brake function (static
objects) differs from the detection
range of the intuiti ve parking assist.
(  P.313) Therefore, even if the
intuitive parking assist detects an
object and provides a warning, the
Parking Support Brake function
(static objects) may not start operat-
ing.
■Objects that the Parking Sup-
port Brake function (static
objects) may not detect
The sensors may not be able to
detect certain objects, such as the
following:
●Pedestrian
●Cotton, snow, and other materials
that are poor re flectors of sonic
waves
●Objects which are not perpendicu-
lar to the ground, are not perpen-
dicular to the traveling direction of
the vehicle, are uneven or are
waving
●Low objects
●Thin objects such as wires,
fences, ropes and signposts
●Objects that are e xtremely close
to the bumper
●Sharply-angled objects
●Tall objects with upper sections
projecting outwards in the direc-

3274-5. Using the driving support systems
4
Driving
tion of your vehicle
■Situations in which the Parking
Support Brake function (static
objects) may not operate
When the shift lever is in N
■Intuitive parking assist buzzer
Regardless of whether the intuitive
parking assist syste m is enabled or
not ( P.310), if the Parking Support
Brake function (static objects) is
enabled ( P.320), the front or rear
sensors detect an object and brake
control and hybrid system output
restriction control are performed, the
intuitive parking assist buzzer will
sound to notify the driver of the
approximate distanc e to the object.
■Situations in which the Parking
Support Brake function (static
objects) may operate even if
there is no possibility of a colli-
sion
In some situations, such as the fol-
lowing, the Parking Support Brake
function (static objects) may operate
even though there is no possibility of
a collision.
●Vehicle surroundings
• When driving on a narrow road
• When driving on a gravel road or in an area with tall grass
• When driving toward a banner, flag, low-hanging branch or boom
barrier (such as those used at rail-
road crossings, toll gates and
parking lots)
• When there is a structure on the roadside (such as when driving in
a narrow tunnel , on a narrow
bridge or on a narrow road)
• When parallel parking
• When there is a rut or hole in the
surface of the road
• When driving on a metal cover
(grating), such as those used for
drainage ditches
• When driving up or down a steep
slope
• If a sensor is hit by a large amount of water, such as when driving on
a flooded road
• When loaded on ships or trucks
• Moving type automatic car wash
• Lift type parking area or multi- story parking lot
• Underground parking area
• Structures on the ground (speed
bumps, cat’s eyes, etc.)
• Differences in height
• When moving straight ahead or
turning right
• Snow-melting pipes
• Devices for detecting vehicles,
such as traffic lig hts, devices for
detecting traffic congestion, or
devices for detecting empty
spaces in parking areas
• Railroad tracks
• H-shaped steel
• When there are vehicles on both sides, or there is a vehicle that
resembles this vehicle
●Weather
• If a sensor is covered with ice, snow, dirt, etc. (when cleared, the
system will return to normal)
• If heavy rain or water strikes a sensor
• When driving in inclement weather such as fog, snow or a sandstorm
• When strong winds are blowing
●Other sonic wave sources
• When vehicle horns, vehicle detectors, motorcycle engines, air
brakes of large vehicles, the clear-

3284-5. Using the driving support systems
ance sonar of other vehicles or
other devices which produce ultra-
sonic waves are near the vehicle
• If a sticker or an electronic compo- nent, such as a backlit license
plate (especially fluorescent type),
fog lights, fender pole or wireless
antenna is insta lled near a sensor
●Changes in the vehicle posture
• If the vehicle is significantly tilted
• If the front of the vehicle is raised or lowered due to the carried load
• If the orientation of a sensor has been changed due t o a collision or
other impact
■Situations in which the Parking
Support Brake function (static
objects) may not operate prop-
erly
In some situations, such as the fol-
lowing, this function may not oper-
ate properly.
●Weather
• When a sensor or the area around a sensor is extremely hot or cold
• When strong winds are blowing
• If a sensor is covered with ice, snow, dirt, etc. (when cleared, the
system will return to normal)
• If heavy rain or water strikes a
sensor
• When driving in inclement weather such as fog, snow or a sandstorm • A sensor is froz
en. (Thawing the
area will resolve this problem.)
●Vehicle surroundings
• When an object that cannot be detected is between the vehicle
and a detected object
• If an object such as a vehicle, motorcycle, bicycle or pedestrian
cuts in front of the vehicle or runs
out from the side of the vehicle
• The vehicle is approaching a tall
or curved curb.
• On an extremely bumpy road, on an incline, on gravel, or on grass.
• The objects draw too close to the sensor.
●Other ultrasonic waves sources
• When vehicle horns, vehicle detectors, motorcycle engines, air
brakes of large vehicles, the clear-
ance sonar of ot her vehicles or
other devices which produce ultra-
sonic waves are near the vehicle
• If a sticker or an electronic compo- nent, such as a backlit license
plate (especially fluorescent type),
fog lights, fender pole or wireless
antenna is installed near a sensor
●Changes in the v ehicle posture
• If the vehicle is significantly tilted
• If the front of the v ehicle is raised
or lowered due to the carried load
• If the orientation of a sensor has
been changed due to a collision or
other impact
• When equipment that may
obstruct a sensor is installed, such
as a bumper protector (an addi-
tional trim strip, etc.), hitch-
mounted bicycle carrier, or snow
plow
• If the suspension has been modi-
fied or tires of a size other than
specified are installed
• If paint or a stic ker is applied to
the sensor

3294-5. Using the driving support systems
4
Driving
*: If equipped
This function will operate in situations such as the following if a vehi-
cle is detected in the traveling direction of the vehicle.
■When reversing, a vehicle is approaching and the brake pedal
is not depressed, or is depressed late
 P.301
Parking Support Brake function (rear-crossing
vehicles)*
If a rear radar sensor detects a vehicle approaching from the
right or left at the rear of the vehicle and the system deter-
mines that the possibility of a collision is high, this function
will perform brake control to reduce the likelihood of an
impact with the approaching vehicle.
Examples of function operation
Types of sensorsWARNING
■To ensure the Parking Sup-
port Brake (rear-crossing
vehicles) can operate prop-
erly
Observe the following precautions
regarding the rear radar sensors
(  P.301). Failure to do so may
cause a sensor t o not operate
properly, and may cause an acci-
dent.

3304-5. Using the driving support systems
■The Parking Support Brake
function (rear-crossing vehi-
cles) will operate when
The function will operate when the
PKSB OFF indicator is not illumi-
nated ( P.93, 95) and all of the fol-
lowing conditions are met:
●Hybrid system output restriction
control
• The Parking Support Brake is enabled.
• The vehicle speed is approxi-
mately 9 mph (15 km/h) or less.
• Vehicles are approaching from the right or left at th e rear of the vehi-
cle at a traveling speed of more
than approximately 5 mph (8
km/h)
• The shift lever is in R.
• The Parking Support Brake deter- mines that a stronger than normal
brake operation is necessary to
avoid a collision with an approach-
ing vehicle.
●Brake control
• Hybrid system output restriction control is operating
• The Parking Support Brake deter- mines that an emergency brake
operation is necessary to avoid a
collision with an approaching vehi-
cle.
■The Parking Support Brake
function (rear-crossing vehi-
cles) will stop operating when
The function will stop operating if
any of the following conditions are
met:
●Hybrid system output restriction
control
• The Parking Support Brake is dis- abled.
• The collision becomes avoidable
with normal brake operation.
• A vehicle is no longer approaching from the right or left at the rear of
the vehicle.
●Brake control
• The Parking Support Brake is dis- abled.
• Approximately 2 seconds have
elapsed since the vehicle was
stopped by brake control.
• The brake pedal is depressed
after the vehicle is stopped by
brake control.
• A vehicle is no longer approaching
from the right or left at the rear of
the vehicle.
■Re-enabling the Parking Sup-
port Brake (rear-crossing vehi-
cles)
 P.322
■Detection area of the Parking
Support Brake function (rear-
crossing vehicles)
The detection area of the Parking
Support Brake function (rear-cross-
ing vehicles) differs from the detec-
tion area of the RCTA function
(  P.306). Therefore, even if the
RCTA function detects a vehicle
and provides an alert, the Parking
Support Brake function (rear-cross-
ing vehicles) may not start operat-
ing.
WARNING
●Do not modify, disassemble or
paint the sensors.
●Do not replace a rear radar sen-
sor with a part o ther than a gen-
uine part.
●Do not damage the rear radar
sensors, and always keep the
radar sensors and their sur-
rounding area on the bumper
clean.
●If the area around a rear radar
sensor is subjected to an
impact, the system may not
operate properly due to a sen-
sor malfunction. Have the vehi-
cle inspected by your Toyota
dealer.
●Observe the rear radar sensor
handling precautions. ( P.301)

3314-5. Using the driving support systems
4
Driving
■Conditions under which the
Parking Support Brake func-
tion (rear-crossing vehicles)
will not detect a vehicle
The Parking Support Brake function
(rear-crossing vehicles) is not
designed to detect the following
types of vehicles and/or objects:
●Vehicles approaching from
directly behind
●Vehicles backing up in a parking
space next to your vehicle
●Vehicles that the sensors cannot
detect due to obstructions
●Vehicles which suddenly acceler-
ate or decelerate near your vehi-
cle
●Guardrails, walls, signs, parked
vehicles and similar stationary
objects
*
●Small motorcycles, bicycles,
pedestrians, etc.*
●Vehicles moving away from your
vehicle
●Vehicles approaching from the
parking spaces next to your vehi-
cle
*
●Objects which are extremely close
to a radar sensor*
●Vehicles which are approaching
from the right or left at the rear of
the vehicle at a traveling speed of
less than approxi mately 5 mph (8
km/h)
●Vehicles which are approaching
from the right or left at the rear of
the vehicle at a traveling speed of
more than approximately 15 mph
(24 km/h)
*: Depending on the conditions,
detection of a v ehicle and/or
object may occur.
■RCTA buzzer
Regardless of whether the RCTA
function is enabled or not ( P.310),
if the Parking Support Brake func-
tion is enabled ( P.320) and brake
control is perfo rmed, a buzzer will
sound to notify the driver.
■Situations in which the system
may operate even though there
is no possibility of a collision
In some situations such as the fol-
lowing, the Parking Support Brake
function (rear-cro ssing vehicles)
may operate even t hough there is
no possibility of a collision.
●When the parking space faces a
street and vehicles are being
driven on the street
●When a detected vehicle turns
while approaching the vehicle
●When a vehicle passes by the
side of your vehicle

3324-5. Using the driving support systems
●When the distance between your
vehicle and metal objects, such as
a guardrail, wall, sign, or parked
vehicle, which may reflect electri-
cal waves toward the rear of the
vehicle, is short
●When there are spinning objects
near your vehicle such as the fan
of an air conditioning unit
●When water is splashed or
sprayed toward t he rear bumper,
such as from a sprinkler
■Situations in which the Parking
Support Brake function (rear-
crossing vehicles) may not
operate properly
In some situations, such as the fol-
lowing, the radar sensors may not
detect an object and this function
may not operate properly
●Stationary objects
●When a sensor or the area around
a sensor is extremely hot or cold
●If the rear bumper is covered with
ice, snow, dirt, etc.
●When it is raining heavily or water
strikes the vehicle
●When the detecti on area of a
radar sensor is obstructed by an
adjacent vehicle
●If the vehicle is s ignificantly tilted
●When equipment that may
obstruct a sensor is installed, such
as a bumper protector (an addi-
tional trim strip, etc.), hitch-
mounted bicycle carrier, or snow
plow
●If the suspension has been modi-
fied or tires of a size other than
specified are installed
●If the front of the v ehicle is raised
or lowered due to the carried load
●If a sticker or an electronic compo-
nent, such as a backlit license
plate (especially fluorescent type),
fog lights, fender pole or wireless
antenna is installed near a radar
sensor
●If the orientation of a radar sensor
has been changed
●When multiple vehicles are
approaching with only a small gap
between each vehicle
●If a vehicle is approaching the rear
of your vehicle rapidly
●Situations in which the radar sen-
sor may not detect a vehicle
• When a vehicle approaches from
the right or left at the rear of the
vehicle while you are turning while
backing up
• When turning while backing up
• When backing out of a shallow angle parking spot

3374-5. Using the driving support systems
4
Driving
*: PCS will also be disabled (only Pre-Collision warning is avail-
able). The PCS warning light will
come on and a message will be
displayed on the multi-information
display. ( P.274)
■When the message is dis-
played on the multi-information
display showing that TRAC has
been disabled even if has
not been pressed
TRAC is temporary deactivated. If
the information continues to show,
contact your Toyota dealer.
■Operating conditions of hill-
start assist control
When the following four conditions
are met, the hill-start assist control
will operate:
●The shift lever is in a position
other than P or N (when starting
off forward/backward on an
upward incline).
●The vehicle is stopped.
●The accelerator pedal is not
depressed.
●The parking brake is not engaged.
■Automatic system cancelation
of hill-start as sist control
The hill-start assis t control will turn
off in any of the following situations:
●The shift lever is shifted to P or N.
●The accelerator pedal is
depressed.
●The parking brake is engaged.
●2 seconds at maximum elapsed
after the brake pedal is released.
■Sounds and vibrations caused
by the ABS, brake assist, VSC,
Trailer Sway Control, TRAC and
hill-start assist control systems
●A sound may be heard from the
engine compartment when the
brake pedal is dep ressed repeat-
edly, when the hybrid system is started or just after the vehicle
begins to move. This sound does
not indicate that a malfunction has
occurred in any of these systems.
●Any of the following conditions
may occur when the above sys-
tems are operating. None of these
indicates that a malfunction has
occurred.
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard also after the vehicle comes to a stop.
■ECB operating sound
ECB operating sound may be heard
in the following cases, but it does
not indicate that a malfunction has
occurred.
●Operating sound heard from the
engine compartment when the
brake pedal is operated.
●Motor sound of the brake system
heard from the f ront part of the
vehicle when the driver’ door is
opened.
●Operating sound heard from the
engine compartment when one or
two minutes passed after the stop
of the hybrid system.
■Active Cornering Assist opera-
tion sounds and vibrations
When the Active Cornering Assist is
operated, operation sounds and
vibrations may be generated from
the brake system, but this is not a
malfunction.
■EPS operation sound
When the steering wheel is oper-
ated, a motor sound (whirring
sound) may be heard. This does not
indicate a malfunction.
■Automatic reactivation of
TRAC, Trailer Sway Control and
VSC systems
After turning the TRAC, Trailer
Sway Control and VSC systems off,
the systems will be a utomatically re-
enabled in the following situations:

3394-5. Using the driving support systems
4
Driving
WARNING
■The ABS does not operate
effectively when
●The limits of tire gripping perfor-
mance have been exceeded
(such as excessively worn tires
on a snow covered road).
●The vehicle hydroplanes while
driving at high speed on wet or
slick roads.
■Stopping distance when the
ABS is operating may exceed
that of normal conditions
The ABS is not designed to
shorten the vehicle’s stopping dis-
tance. Always maintain a safe dis-
tance from the vehicle in front of
you, especially in the following sit-
uations:
●When driving on d irt, gravel or
snow-covered roads
●When driving with tire chains
●When driving over bumps in the
road
●When driving over roads with
potholes or uneven surfaces
■TRAC/VSC may not operate
effectively when
Directional control and power may
not be achievable while driving on
slippery road surfaces, even if the
TRAC/VSC system is operating.
Drive the vehicle carefully in con-
ditions where stability and power
may be lost.
■Active Cornering Assist does
not operate effectively when
●Do not overly rely on Active
Cornering Assist. Active Corner-
ing Assist may not operate
effectively when accelerating
down slopes or driving on slip-
pery road surfaces.
●When Active Corn ering Assist
frequently operates, Active Cor-
nering Assist may temporarily
stop operating to ensure proper
operation of the brakes, TRAC
and VSC.
■Hill-start assist control does
not operate effectively when
●Do not overly rely on hill-start
assist control. Hill-start assist
control may not operate effec-
tively on steep inclines and
roads covered with ice.
●Unlike the parking brake, hill-
start assist control is not
intended to hold the vehicle sta-
tionary for an extended period
of time. Do not attempt to use
hill-start assist control to hold
the vehicle on an incline, as
doing so may lead to an acci-
dent.
■When the
TRAC/ABS/VSC/Trailer Sway
Control is activated
The slip indicator flashes. Always
drive carefully. Reckless driving
may cause an accident. Exercise
particular care when the indicator
light flashes.
■When the TRAC/VSC/Trailer
Sway Control systems are
turned off
Be especially careful and drive at
a speed appropriate to the road
conditions. As these are the sys-
tems to help ensure vehicle stabil-
ity and driving force, do not turn
the TRAC/VSC/Tra iler Sway Con-
trol systems off unless necessary.
Trailer Sway Control is part of the
VSC system and will not operate
if VSC is turned off or experiences
a malfunction.